Abstract
A temperature compensation circuit including a magnetic coil, wherein an electrical resistance of the magnetic coil increases with increasing temperature. The temperature compensation circuit is electrically connected to the magnetic coil and includes at least has one component whose electrical resistance decreases with increasing temperature. A plurality of components having electrical resistances decreasing with increasing temperature, increases with increasing temperature, and/or substantially constant with increasing temperature may also be provided.
Claims
1. A temperature compensation circuit comprising: a magnetic coil with an electrical coil resistance increasing with increasing temperature; a temperature compensation circuit electrically connected to the magnetic coil; and a first component having an electrical resistance decreasing with increasing temperature.
2. The temperature compensation circuit according to claim 1, wherein the first component is a resistor.
3. The temperature compensation circuit according to claim 1, wherein the temperature compensation circuit is connected in series with the coil.
4. The temperature compensation circuit according to claim 1, wherein the temperature compensation circuit or the first component is thermally coupled to the coil.
5. The temperature compensation circuit according to claim 1, wherein the first component is connected in parallel with a second component having a substantially constant electrical resistance with increasing temperature.
6. The temperature compensation circuit according to claim 1, wherein the first component is connected in series with a second component having a substantially constant electrical resistance with increasing temperature.
7. The temperature compensation circuit according to claim 1, wherein the first component is connected in parallel or in series with a second component with an electrical resistance increasing with increasing temperature, and wherein the second component is thermally coupled to the coil.
8. The temperature compensation circuit according to claim 1, further comprising a plurality of components having electrical resistances decreasing with increasing temperature, increases with increasing temperature, and/or substantially constant with increasing temperature.
9. An actuator comprising a temperature compensation circuit according to claim 1.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] An exemplary embodiment of the invention is explained in more detail below with reference to the drawings.
[0024] FIG. 1 shows schematically a magnetic coil according to the invention.
[0025] FIG. 2 shows, as an example, an actuator (solenoid valve) constructed with the magnetic coil according to the invention.
[0026] FIG. 3 shows a circuit diagram for a temperature compensation circuit according to one embodiment.
[0027] FIG. 4A shows a circuit diagram for a temperature compensation circuit according to another embodiment.
[0028] FIG. 4B shows a circuit diagram for a temperature compensation circuit according to a further embodiment.
[0029] FIG. 5 shows a circuit diagram for a component whose electrical resistance increases with increasing temperature and which can be used in a temperature compensation circuit according to FIGS. 3-4B.
[0030] FIG. 6 shows another circuit diagram for a component whose electrical resistance increases with increasing temperature and which can be used in a temperature compensation circuit according to FIGS. 3-4B.
DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION
[0031] The magnetic coil 1 shown schematically in FIG. 1 has a coil 2 whose electrical resistance increases with increasing temperature. In order to compensate for this, a passive circuit 3 with NTC behavior is connected in series with the coil.
[0032] The actuator 4 shown in FIG. 2 has an anchor 5 actuated by the coil 2 and, on a circuit board, the temperature compensation circuit 3.
[0033] FIG. 2 denotes a coil, and a bracket, by means of which the actuator can be attached, for example. Only FIG. 2 denotes a cover, and the valve body, which is substantially Z-shaped in the case shown, wherein in the case shown the central, a short leg is substantially perpendicular to two other legs, which correspond to an inlet and an outlet. Furthermore, in the example shown, a valve tappet 5 is provided in the central leg of the Z in order to open or close the fluid passage. In the example shown, the valve tappet also moves substantially perpendicularly to the inlet and the outlet, and a plane of the valve seat with which the valve tappet interacts, in particular its plate provided with a seal in the case shown, is substantially parallel to the flow direction in the inlet and the outlet.
[0034] As can be seen in FIG. 2, an electronics housing, which for example has a printed circuit board with electronic components, is integrated into the actuator. In the case shown, the electronics housing is located between a base plate of the coil and the valve body 4. As can be seen in the right-hand portion of the figure, lines for the voltage supply and a switching input run from the printed circuit board to a plug-in socket, which can also be designed as a plug. It should be mentioned with respect to the structure shown in FIG. 2, in which the electronics housing is located between the coil and the valve body 4 or valve housing, that the electronics housing with the electronics provided therein, such as, e.g., a printed circuit board, electronic components, and all the components further mentioned herein, also according to FIG. 2 can be located above the coil, i.e., on the other side compared to the valve housing, or in any other way next to the coil. The last-mentioned arrangement means a displacement of the electronics housing relative to the coil in the direction perpendicular to the direction of movement of the anchor in the coil.
[0035] As shown in FIG. 2, the printed circuit board can surround the valve tappet and/or a guide provided therefore, and it can be oriented substantially perpendicular to the direction of movement of the valve tappet. The lines extending from the printed circuit board can initially be directed away from the coil, then extend substantially at an angle of 90 and extend essentially laterally alongside the coil at an angle of 70 to 90 in the direction of the coil.
[0036] FIG. 3 shows an example of a temperature compensation circuit 1 for an embodiment of the present invention. Here, the coil 2 is connected to a component 3 whose electrical resistance is substantially constant with increasing temperature (e.g., a resistor), and a component 4 whose electrical resistance decreases with increasing temperature. The component 3 and the component 4 are connected in parallel. Since these two components are used and they are connected in parallel, it is possible to compensate for an increase in the resistance of the coil 2 with increasing temperature. In particular, a total resistance of these two components is produced by the parallel connection of the component 3 and the component 4, which is lower than the sum of the resistances of these two components.
[0037] FIG. 4A shows a further example of a temperature compensation circuit 1 for an embodiment of the present invention. In contrast to FIG. 3, the component 3 and the component 4, whose electrical resistance decreases with increasing temperature, are connected in series here. In this case too, by using these two components 3, 4 it can be ensured that the increase in the resistance of the coil is well compensated with increasing temperature. In this circuitry, the total resistance of these two components is the sum of the individual resistances, i.e., in contrast to FIG. 3, this resistance is higher than the resistance value of each individual component.
[0038] FIG. 4B shows, in a sense, a combination of the temperature compensation circuits of FIGS. 3 and 4A. In this case, a component 3a,whose electrical resistance is substantially constant with increasing temperature, is connected in parallel with the component 4, whose resistance decreases with increasing temperature. However, this parallel circuitry is connected in series with a further component 3, whose resistance is substantially constant with increasing temperature. For reasons which substantially follow from the above considerations of FIGS. 3 and 4A, in this case the overall resistance of this circuitry is limited both upwards and downwards.
[0039] FIGS. 5 and 6 each show examples of how the components 4, 4, whose electrical resistance decreases with increasing temperature, can be designed. In both cases, a component 5 is used whose electrical resistance decreases with increasing temperatures. A further component 6, whose electrical resistance increases with increasing temperature, is provided connected in parallel (FIG. 6) and connected in series therewith (FIG. 5). By providing such a component, the non-linearity of both the coil 2 and the component 5, whose electrical resistance decreases with increasing temperature, can be compensated so that the overall resistance of the circuitry consisting of coil and temperature compensation circuit remains constant in an acceptable range, ensuring good controllability. The component 6, whose electrical resistance increases with increasing temperature, can be formed here and also generally by a cold-conducting thermistor.
[0040] In this regard, it can also be useful to provide more than one component 3, 3, 3, 3a with constant electrical resistance, more than one component 4, 4, 4 with an electrical resistance which decreases with increasing temperature, and more than one component 6 whose electrical resistance increases with increasing temperature. These components can each replace the components individually shown in the figures.
